结构工程师2025，Vol.41Issue(4)：102-110,9.DOI:10.15935/j.cnki.jggcs.202504.0012
先张法UHPC-NC组合小箱梁设计与弯曲性能试验
Design and Bending Performance Test of Pretensioned UHPC-NC Composite Small Box Girders
摘要
Abstract
This study proposes a lightweight and industrialized pretensioned composite small box girder structure combining Ultra-High Performance Concrete(UHPC)and ordinary concrete(NC),leveraging the superior mechanical properties of UHPC.Compliance verification with the Swiss ultra-high performance fibre reinforced concrete structural code and the Chinese bridge design code confirms that the composite beam satisfies Class A prestressed component requirements while achieving a 30%weight reduction compared to conventional NC box girders of identical span.To validate flexural performance,a bending failure test was conducted on a scaled specimen.As observed,upon ordinary reinforcement yielding,the UHPC at the bottom edge completed tensile strain hardening with strains of 1 930-2 100 με,developing fine cracks below 0.2 mm width.Steel strand yielding marked the stiffness degradation inflection point,where UHPC compressive strain at the top edge reached 1 060 με(below its ultimate strain),followed by steel fiber pullout and tensile zone stress redistribution.Final failure occurred due to NC top slab crushing,yielding a displacement ductility coefficient of 2.3.Scaling analysis incorporating a structural importance factor of 1.1 indicates that for the prototype beam,the partial factor for vehicle loads under fundamental combinations is 2.03(exceeding the standard 1.4),while the frequent value coefficient under frequent combinations is 0.87(surpassing the standard 0.7).The pretensioned system demonstrates enhanced prestressing efficiency in UHPC sections and effective post-cracking material collaboration,confirming its viability for practical applications.关键词
桥梁工程/UHPC/组合梁/抗弯试验/极限状态Key words
bridge engineering/UHPC/composite beam/bending test/ultimate state分类
建筑与水利引用本文复制引用
董夏鑫..先张法UHPC-NC组合小箱梁设计与弯曲性能试验[J].结构工程师,2025,41(4):102-110,9.基金项目
上海市自然科学基金项目(17ZR1421000) （17ZR1421000）
